Polyacrylonitrile-MV50000

Catalog	ACM25014419-8
CAS	25014-41-9
Structure
Molecular Weight	50000
Storage	Room temperature

Case Study

Preparation of Polyacrylonitrile Membranes by Thermally Induced Phase Separation

Wu, Qing-Yun, et al. Journal of membrane science, 2012, 409, 355-364.

A thermally induced phase separation (TIPS) process is reported for the preparation of polyacrylonitrile (PAN, Mη= 50,000 g/mol) membranes using dimethyl sulfone (DMSO2) and glycerol as mixed diluents. The preparation of PAN membranes with lamellar, needle-like, and honeycomb-like pores was achieved by adjusting the reaction conditions such as glycerol content, polymer concentration, and cooling bath. The obtained PAN membranes are suitable for microfiltration or ultrafiltration processes in water treatment, or as supports for enzyme immobilization or for the preparation of composite membranes based thereon.
Preparation of PAN membranes
· The mixture of PAN/DMSO2/glycerol was heated to 160 °C until it formed a uniform solution. Once the air bubbles were removed, the solution was swiftly poured into a stainless steel mold (approximately 200 m thick) that had been preheated to 160 °C in an oven.
· Next, the mold containing the modeling solution was rapidly immersed in a cooling bath (water bath at 4, 30, or 60 °C or air bath at 30 or 60 °C) to facilitate phase separation.
· After the solution completely solidified, the newly formed membrane was removed from the mold and soaked in deionized water at 40 °C for 24 hours. This process resulted in a wet PAN membrane following the extraction of the solvent.
· To prevent pore collapse during drying, the wet membrane was washed using a sequence of ethanol and hexane and then vacuum-dried at 40 °C for 24 hours.

Effect of Polymer Molecular Weight on Polyacrylonitrile Homopolymer Membranes

Rekha Panda, et al. Polymer Engineering & Science, 2014, 54(10), 2375-2391.

Polyacrylonitrile (PAN) is an important base polymer for casting porous membranes. PAN membranes were prepared from PAN homopolymers with different molecular weights (50, 100, 150, and 250 kDa) by phase inversion technique using dimethylformamide as solvent, and their performance differences were compared.
· As the concentration of the 50 kDa homopolymer PAN increases, the membrane's density rises. The permeability decreases from 2.5 × 10^-10 m/Pa s to 0.5 × 10^-10 m/Pa s when the concentration shifts from 10% to 15% by weight. In tandem, the membrane's molecular weight cutoff (MWCO) reduces from 82,000 to 65,000, and the average pore diameter shrinks from approximately 60 nm to 30 nm.
· At a concentration of 15% by weight, membranes exhibit increased porosity as the molecular weight of PAN escalates from 50 kDa to 250 kDa. The permeability of these membranes rises from 0.5 × 10^-11 m/Pa s to 12 × 10 ^-11 m/Pa s. The MWCO also increases correspondingly, moving from 65,000 to 88,000. Data from contact angle measurements indicate that membranes become more hydrophilic as the molecular weight of PAN increases.
· The addition of PEG 200 results in the membrane with the lowest permeability, measured at 3.2 × 10 ^-11 m/Pa s. Increasing the molecular weight of PEG at a constant concentration of 5% leads to greater porosity in the membranes. Using PEG 400 at 5% with 15% PAN of 50 kDa molecular weight yields an MWCO of 60,000.